Method and apparatus for locally intensifying brightness in a video display device

Abstract

A method for intensifying brightness of a predetermined pattern in a video display comprises detecting the duration of predetermined portions of said video signal; detecting the predetermined pattern in these predetermined portions of said video signal; and producing an output control signal in response to each detection of the predetermined pattern of at least a predetermined duration. Apparatus is provided for carrying out the method.

The invention is claimed as follows: 
     
       1. In a method for intensifying brightness of a predetermined pattern in a video display the improvement comprising the steps of: detecting the duration of predetermined portions of said video signal, including the step of simultaneously delaying said video signal by each of a predetermined plural number of predetermined time delay factors; detecting said predetermined pattern in said predetermined portions of said video signal including frequency filtering said time delayed signals; and producing an output control signal in response to each detection of said predetermined pattern of at least a predetermined duration. 
     
     
       2. The improvement according to claim 1 wherein the step of frequency filtering further includes separately frequency filtering each of said delayed video signals with one of a corresponding plurality of predetermined filter characteristics. 
     
     
       3. The improvement according to claim 2 wherein the step of duration detecting further comprises detecting the simultaneous presence of a predetermined plural number of said separately filtered signals. 
     
     
       4. The improvement according to claim 1 and further including the steps of receiving a synchronizing signal; assigning predetermined positions in a register in accordance with said synchronizing signal; and writing into said register information corresponding to the desired brightness distribution of an image to be displayed upon said video display in response to said output control signal and said synchronizing signal. 
     
     
       5. In an apparatus for intensifying brightness of a predetermined pattern in a video display, the improvement comprising: duration detecting means comprising a plurality of time delay circuit means arranged in parallel circuit for delaying said video signal by each of a predetermined plurality of predetermined time delay factors to thereby produce a corresponding plurality of time delayed video signals; pattern detecting means comprising filtering circuit means responsive to a predetermined video signal frequency distribution for detecting a predetermined pattern of said time delayed signals corresponding to said predetermined portions of said video signal and for producing a corresponding pattern detection signal; and control means for producing an output control signal in response to presence of said pattern detection signal. 
     
     
       6. The improvement in accordance with claim 5 wherein said filtering circuit means comprises a plurality of filter circuits, each coupled to filter one of said plurality of time delayed video signals and each responsive to a predetermined frequency distribution of the time delayed video signal for producing one said pattern detection signal. 
     
     
       7. The improvement in accordance with claim 6 wherein said duration detecting means further comprises AND circuit means responsive to the presence of said pattern detection signals from a predetermined plural number of said filter circuits for producing said output control signal. 
     
     
       8. The improvement in accordance with claim 5 and further including register means for storing information corresponding to the desired brightness level at a plurality of locations on said video display; counting circuit means responsive to a synchronizing signal for indicating locations in said register; and register writing means responsive to said counting means and to said control output signal for writing into said register information which corresponds to a desired brightness level at each of said locations on said video display. 
     
     
       9. In a method for intensifying brightness of a predetermined pattern in a video display, the improvement comprising the steps of: detecting the duration of predetermined portions of said video signal and producing a corresponding duration signal; comparing the level of said duration signal with a predetermined threshold level and producing an output pulse for each signal which is in excess of said predetermined threshold level; detecting said predetermined pattern in said predetermined portions of said video signal; and producing an output control signal in response to each detection of said predetermined pattern of at least a predetermined duration and in excess of said predetermined threshold level. 
     
     
       10. In apparatus for intensifying brightness of a predetermined pattern in a video display, the improvement comprising: duration detecting means for detecting the duration of predetermined portions of said video signal and producing a corresponding duration signal; threshold detection means for comparing the level of the duration signal with a predetermined threshold level and producing an output pulse for each signal which is in excess of said predetermined threshold level; pattern detecting means for detecting a predetermined pattern of said output pulses corresponding to predetermined portions of said video signal and for producing a corresponding pattern detection signal; and control means for producing an output control signal in response to presence of said pattern detection signal.